This invention relates to an operating machine shiftably mounted on a track alongside a coke oven at a coking plant. More particularly, this invention relates to an assembly at the coke oven for controlling the positioning of the operating machine along the track.
A coking plant customarily includes a coke oven divided into several chambers disposed seriatim. Each chamber is provided on its sides and at the top with openings closable by respective chamber doors. Operating machines are shiftably mounted on tracks which run along both lateral sides and along the top side of the coke oven, the operating machines being designed to charge and discharge the oven chambers after the respective chamber doors are opened. At the end of the coking process, the oven chambers are discharged by pushing the glowing coke out from the chambers onto a quenching carriage. In order to ensure smooth operation of the coking plant, it is necessary to position the operating machines precisely at predetermined operating stations beside the chamber doors of the coke oven and, in addition, to position the operating machines at the correct time.
German Laid-Open Application (Deutsche Offenlegungsschrift) No. 26 48 049 discloses a method for controlling and monitoring the operation of coke oven operating machines, in which method a travel distance determination is made and which method attempts to attain fine tuning and synchronization in the positioning of the operating machines alongside the coke oven. Code plates are disposed at the operating stations of the individual coke oven operating machines, while reading devices are attached to the operating machines for detecting information coded in the code plates. The code plates simultaneously serve to mark the centers of the respective oven chambers and to fine-tune the positioning of the operating machines at the operating stations. By comparing the actual positions of the operating machines, as sensed by the reading devices in cooperation with the code plates, with the desired destinations in accordance with a current stage of a coke oven operating sequence, a central control unit generates signals for controlling the propulsion drives of the operating machines so that the machines are stopped at precise positions at the operating stations. The centers of the individual oven chambers are marked by magnets disposed on the code plates, the locations of the magnets being detected by corresponding magnetic sensors on the operating machines. The reading devices generate travel-direction reference values in the form of positive or negative voltages in accordance with the distances of the operating machines from respective operating station centers and the directions of motions of the operating machines with respect to respective operating stations.
A positioning method utilizing magnetic sensor and magnetic position markers is disadvantageous owing to an inherently low positioning accuracy resulting from the relative flatness, in the vicinity of a zero point, of the graph of the magnetic field strength as a function of the direction of motion, the control voltages generated by Hall effect generators being concomitantly flattened.
An object of the present invention is to provide an improved assembly for controlling the positioning of coke oven operating machines along respective tracks.
A more particular object of the present invention is to provide such an assembly in which the positioning of the operating machines alongside a coke oven is accurate to millimeters.
Another particular object of the present invention is to provide such as assembly which is relatively insensitive to dust and heat.